Humans interface with electronic devices in a variety of applications, and the need for a more natural, easy-to-use, and informative interface device is a constant concern. Some applications involve interacting directly with computer-generated environments. Interface devices are used extensively with computer systems in the implementation of computer-controlled games, simulations, and other applications. A computer system such as a personal computer, home video game console, and portable computer can display a visual environment to a user on a display device. Users can interact with the displayed environment by inputting commands or data from the interface device. Popular interface devices include joysticks, mice, trackballs, styluses, tablets, pressure spheres, foot or hand pedals, or the like, that are connected to the computer system controlling the displayed environment. The computer updates the environment in response to the user's manipulation of a moved manipulandum, such as a joystick handle or mouse, and provides visual feedback to the user using the display screen.
In some interface devices, haptic (e.g., tactile and/or kinesthetic) feedback is also provided to the user. These types of interface devices can provide physical sensations to the user manipulating the interface device. For instance, motors or other actuators of the interface device are coupled to the manipulandum and are connected to the controlling computer system. The computer system receives sensor signals from the interface device and sends appropriate haptic control signals to the actuators in conjunction with host events. The actuators then provide forces on the manipulandum. The computer system can thus convey physical sensations to the user in conjunction with other visual and auditory feedback as the user is contacting the manipulandum. Commercially available interface devices with haptic feedback include the ForceFX joystick from CH Products, Inc.; the Wingman Force joystick and Wingman Formula Force steering wheel from Logitech, Inc.; and the Sidewinder Force Feedback Pro joystick from Microsoft Corporation.